Separate regions of the hypothalamus appear to have profound and opposite effects on animals' motivated behavior (e.g., feeding and attack). However, it now appears that these same brain areas can influence animals' basic sensorimotor functions as well. The sensorimotor changes which result for stimulation or destruction of the medial or lateral hypothalamus contribute to their effects on feeding and attack. It now appears likely that ascending catecholamine-containing neural systems, particularly the nigrostriatal dopamine bundle, are particularly important in mediating the lateral hypothalamic influence over sensorimotor functions. I propose (1) to examine in detail the neural basis for these sensorimotor impairments seen after lateral hypothalamic damage, (2) to pursue their relevance to the changes in motivated behavior apparent after such lesions, and (3) to investigate the neurochemical changes which might underlie the hyperresponsiveness to sensory stimuli seen after medial hypothalamic damage. BIBLIOGRAPHIC REFERENCES: Marshall, J. F., Friedman, M. I., and Heffner, T.G. Reduced anorexic and locomotor stimulant action of D-amphetamine in alloxan-diabetic rats. Brain Research, 1976, 111, 428-432. Marshall, J. F., Levitan, D., and Stricker, E. M. Activation-induced restoration of sensorimotor functions in rats with dopamine-depleting brain lesions. J. Compar. Physiol. Psychol. 1976, 90, 536-546.